#ifndef _NETP_SECURITY_MURMURHASH_HPP
#define _NETP_SECURITY_MURMURHASH_HPP

#include <netp.hpp>


namespace netp { namespace security {

	/**
	 * borrow from https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp
	 * @add endian consideration
	*/
#ifndef _MSC_VER
	__NETP_FORCE_INLINE uint32_t _rotl(uint32_t x, int8_t r) { return (x << r) | (x >> (32 - r)); }
	__NETP_FORCE_INLINE uint64_t _rotl64(uint64_t x, int8_t r) { return (x << r) | (x >> (64 - r)); }
#endif

#define ROTL32(x,y)	_rotl(x,y)
#define ROTL64(x,y)	_rotl64(x,y)
#define BIG_CONSTANT(x) (x##LLU)

	//-----------------------------------------------------------------------------
	// Block read - if your platform needs to do endian-swapping or can only
	// handle aligned reads, do the conversion here

	__NETP_FORCE_INLINE uint32_t getblock32(const uint32_t * p, int i)
	{
		return netp::bytes_helper::read_u32((netp::byte_t*)(p + i));
//		return p[i];
	}

	__NETP_FORCE_INLINE uint64_t getblock64(const uint64_t * p, int i)
	{
		return netp::bytes_helper::read_u64((netp::byte_t*)(p + i));
//		return p[i];
	}

	//-----------------------------------------------------------------------------
	// Finalization mix - force all bits of a hash block to avalanche

	__NETP_FORCE_INLINE uint32_t fmix32(uint32_t h)
	{
		h ^= h >> 16;
		h *= 0x85ebca6b;
		h ^= h >> 13;
		h *= 0xc2b2ae35;
		h ^= h >> 16;

		return h;
	}

	//----------

	__NETP_FORCE_INLINE ::uint64_t fmix64(uint64_t k)
	{
		k ^= k >> 33;
		k *= BIG_CONSTANT(0xff51afd7ed558ccd);
		k ^= k >> 33;
		k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
		k ^= k >> 33;

		return k;
	}

	//-----------------------------------------------------------------------------

	void MurmurHash3_x86_32(const void * key, int len,
		uint32_t seed, void * out)
	{
		const uint8_t * data = (const uint8_t*)key;
		const int nblocks = len / 4;

		uint32_t h1 = seed;

		const uint32_t c1 = 0xcc9e2d51;
		const uint32_t c2 = 0x1b873593;

		//----------
		// body

		const uint32_t * blocks = (const uint32_t *)(data + nblocks * 4);

		for (int i = -nblocks; i; i++)
		{
			uint32_t k1 = getblock32(blocks, i);

			k1 *= c1;
			k1 = ROTL32(k1, 15);
			k1 *= c2;

			h1 ^= k1;
			h1 = ROTL32(h1, 13);
			h1 = h1 * 5 + 0xe6546b64;
		}

		//----------
		// tail

		const uint8_t * tail = (const uint8_t*)(data + nblocks * 4);

		uint32_t k1 = 0;

		switch (len & 3)
		{
		case 3: k1 ^= tail[2] << 16;
		case 2: k1 ^= tail[1] << 8;
		case 1: k1 ^= tail[0];
			k1 *= c1; k1 = ROTL32(k1, 15); k1 *= c2; h1 ^= k1;
		};

		//----------
		// finalization

		h1 ^= len;

		h1 = fmix32(h1);

		netp::bytes_helper::write_u32(h1, (netp::byte_t*)out);
//		*(uint32_t*)out = h1;
	}

	//-----------------------------------------------------------------------------

	void MurmurHash3_x86_128(const void * key, const int len,
		uint32_t seed, void * out)
	{
		const uint8_t * data = (const uint8_t*)key;
		const int nblocks = len / 16;

		uint32_t h1 = seed;
		uint32_t h2 = seed;
		uint32_t h3 = seed;
		uint32_t h4 = seed;

		const uint32_t c1 = 0x239b961b;
		const uint32_t c2 = 0xab0e9789;
		const uint32_t c3 = 0x38b34ae5;
		const uint32_t c4 = 0xa1e38b93;

		//----------
		// body

		const uint32_t * blocks = (const uint32_t *)(data + nblocks * 16);

		for (int i = -nblocks; i; i++)
		{
			uint32_t k1 = getblock32(blocks, i * 4 + 0);
			uint32_t k2 = getblock32(blocks, i * 4 + 1);
			uint32_t k3 = getblock32(blocks, i * 4 + 2);
			uint32_t k4 = getblock32(blocks, i * 4 + 3);

			k1 *= c1; k1 = ROTL32(k1, 15); k1 *= c2; h1 ^= k1;

			h1 = ROTL32(h1, 19); h1 += h2; h1 = h1 * 5 + 0x561ccd1b;

			k2 *= c2; k2 = ROTL32(k2, 16); k2 *= c3; h2 ^= k2;

			h2 = ROTL32(h2, 17); h2 += h3; h2 = h2 * 5 + 0x0bcaa747;

			k3 *= c3; k3 = ROTL32(k3, 17); k3 *= c4; h3 ^= k3;

			h3 = ROTL32(h3, 15); h3 += h4; h3 = h3 * 5 + 0x96cd1c35;

			k4 *= c4; k4 = ROTL32(k4, 18); k4 *= c1; h4 ^= k4;

			h4 = ROTL32(h4, 13); h4 += h1; h4 = h4 * 5 + 0x32ac3b17;
		}

		//----------
		// tail

		const uint8_t * tail = (const uint8_t*)(data + nblocks * 16);

		uint32_t k1 = 0;
		uint32_t k2 = 0;
		uint32_t k3 = 0;
		uint32_t k4 = 0;

		switch (len & 15)
		{
		case 15: k4 ^= tail[14] << 16;
		case 14: k4 ^= tail[13] << 8;
		case 13: k4 ^= tail[12] << 0;
			k4 *= c4; k4 = ROTL32(k4, 18); k4 *= c1; h4 ^= k4;

		case 12: k3 ^= tail[11] << 24;
		case 11: k3 ^= tail[10] << 16;
		case 10: k3 ^= tail[9] << 8;
		case  9: k3 ^= tail[8] << 0;
			k3 *= c3; k3 = ROTL32(k3, 17); k3 *= c4; h3 ^= k3;

		case  8: k2 ^= tail[7] << 24;
		case  7: k2 ^= tail[6] << 16;
		case  6: k2 ^= tail[5] << 8;
		case  5: k2 ^= tail[4] << 0;
			k2 *= c2; k2 = ROTL32(k2, 16); k2 *= c3; h2 ^= k2;

		case  4: k1 ^= tail[3] << 24;
		case  3: k1 ^= tail[2] << 16;
		case  2: k1 ^= tail[1] << 8;
		case  1: k1 ^= tail[0] << 0;
			k1 *= c1; k1 = ROTL32(k1, 15); k1 *= c2; h1 ^= k1;
		};

		//----------
		// finalization

		h1 ^= len; h2 ^= len; h3 ^= len; h4 ^= len;

		h1 += h2; h1 += h3; h1 += h4;
		h2 += h1; h3 += h1; h4 += h1;

		h1 = fmix32(h1);
		h2 = fmix32(h2);
		h3 = fmix32(h3);
		h4 = fmix32(h4);

		h1 += h2; h1 += h3; h1 += h4;
		h2 += h1; h3 += h1; h4 += h1;

		((uint32_t*)out)[0] = h1;
		((uint32_t*)out)[1] = h2;
		((uint32_t*)out)[2] = h3;
		((uint32_t*)out)[3] = h4;
	}

	//-----------------------------------------------------------------------------

	void MurmurHash3_x64_128(const void * key, const int len,
		const uint32_t seed, void * out)
	{
		const uint8_t * data = (const uint8_t*)key;
		const int nblocks = len / 16;

		uint64_t h1 = seed;
		uint64_t h2 = seed;

		const uint64_t c1 = BIG_CONSTANT(0x87c37b91114253d5);
		const uint64_t c2 = BIG_CONSTANT(0x4cf5ad432745937f);

		//----------
		// body

		const uint64_t * blocks = (const uint64_t *)(data);

		for (int i = 0; i < nblocks; i++)
		{
			uint64_t k1 = getblock64(blocks, i * 2 + 0);
			uint64_t k2 = getblock64(blocks, i * 2 + 1);

			k1 *= c1; k1 = ROTL64(k1, 31); k1 *= c2; h1 ^= k1;

			h1 = ROTL64(h1, 27); h1 += h2; h1 = h1 * 5 + 0x52dce729;

			k2 *= c2; k2 = ROTL64(k2, 33); k2 *= c1; h2 ^= k2;

			h2 = ROTL64(h2, 31); h2 += h1; h2 = h2 * 5 + 0x38495ab5;
		}

		//----------
		// tail

		const uint8_t * tail = (const uint8_t*)(data + nblocks * 16);

		uint64_t k1 = 0;
		uint64_t k2 = 0;

		switch (len & 15)
		{
		case 15: k2 ^= ((uint64_t)tail[14]) << 48;
		case 14: k2 ^= ((uint64_t)tail[13]) << 40;
		case 13: k2 ^= ((uint64_t)tail[12]) << 32;
		case 12: k2 ^= ((uint64_t)tail[11]) << 24;
		case 11: k2 ^= ((uint64_t)tail[10]) << 16;
		case 10: k2 ^= ((uint64_t)tail[9]) << 8;
		case  9: k2 ^= ((uint64_t)tail[8]) << 0;
			k2 *= c2; k2 = ROTL64(k2, 33); k2 *= c1; h2 ^= k2;

		case  8: k1 ^= ((uint64_t)tail[7]) << 56;
		case  7: k1 ^= ((uint64_t)tail[6]) << 48;
		case  6: k1 ^= ((uint64_t)tail[5]) << 40;
		case  5: k1 ^= ((uint64_t)tail[4]) << 32;
		case  4: k1 ^= ((uint64_t)tail[3]) << 24;
		case  3: k1 ^= ((uint64_t)tail[2]) << 16;
		case  2: k1 ^= ((uint64_t)tail[1]) << 8;
		case  1: k1 ^= ((uint64_t)tail[0]) << 0;
			k1 *= c1; k1 = ROTL64(k1, 31); k1 *= c2; h1 ^= k1;
		};

		//----------
		// finalization

		h1 ^= len; h2 ^= len;

		h1 += h2;
		h2 += h1;

		h1 = fmix64(h1);
		h2 = fmix64(h2);

		h1 += h2;
		h2 += h1;

		((uint64_t*)out)[0] = h1;
		((uint64_t*)out)[1] = h2;
	}
}}
#endif